reconnect support

pull/2590/head
yang-g 10 years ago
parent 5553eb3ee2
commit b4e262cb60
  1. 63
      src/core/client_config/subchannel.c

@ -44,6 +44,12 @@
#include "src/core/transport/connectivity_state.h"
#include "src/core/surface/channel.h"
#define GRPC_SUBCHANNEL_MIN_CONNECT_TIMEOUT_SECONDS 20
#define GRPC_SUBCHANNEL_INITIAL_CONNECT_BACKOFF_SECONDS 1
#define GRPC_SUBCHANNEL_RECONNECT_BACKOFF_MULTIPLIER 1.6
#define GRPC_SUBCHANNEL_RECONNECT_MAX_BACKOFF_SECONDS 120
#define GRPC_SUBCHANNEL_RECONNECT_JITTER 0.2
typedef struct {
/* all fields protected by subchannel->mu */
/** refcount */
@ -125,6 +131,8 @@ struct grpc_subchannel {
int have_alarm;
/** our alarm */
grpc_alarm alarm;
/** current random value */
gpr_int32 random;
};
struct grpc_subchannel_call {
@ -264,6 +272,10 @@ void grpc_subchannel_del_interested_party(grpc_subchannel *c,
grpc_pollset_set_del_pollset(c->pollset_set, pollset);
}
static gpr_int32 random_seed() {
return gpr_time_to_millis(gpr_now(GPR_CLOCK_REALTIME));
}
grpc_subchannel *grpc_subchannel_create(grpc_connector *connector,
grpc_subchannel_args *args) {
grpc_subchannel *c = gpr_malloc(sizeof(*c));
@ -284,6 +296,7 @@ grpc_subchannel *grpc_subchannel_create(grpc_connector *connector,
c->mdctx = args->mdctx;
c->master = args->master;
c->pollset_set = grpc_client_channel_get_connecting_pollset_set(parent_elem);
c->random = random_seed();
grpc_mdctx_ref(c->mdctx);
grpc_iomgr_closure_init(&c->connected, subchannel_connected, c);
grpc_connectivity_state_init(&c->state_tracker, GRPC_CHANNEL_IDLE,
@ -307,10 +320,9 @@ static void continue_connect(grpc_subchannel *c) {
}
static void start_connect(grpc_subchannel *c) {
gpr_timespec now = gpr_now(GPR_CLOCK_REALTIME);
c->next_attempt = now;
c->backoff_delta = gpr_time_from_seconds(1, GPR_TIMESPAN);
c->backoff_delta = gpr_time_from_seconds(
GRPC_SUBCHANNEL_INITIAL_CONNECT_BACKOFF_SECONDS, GPR_TIMESPAN);
c->next_attempt = gpr_time_add(gpr_now(GPR_CLOCK_REALTIME), c->backoff_delta);
continue_connect(c);
}
@ -576,6 +588,34 @@ static void publish_transport(grpc_subchannel *c) {
}
}
/* Generate a random number between 0 and 1. */
static double generate_uniform_random_number(grpc_subchannel *c) {
c->random = (1103515245 * c->random + 12345) % ((gpr_uint32)1 << 31);
return c->random / (double)((gpr_uint32)1 << 31);
}
/* Update backoff_delta and next_attempt in subchannel */
static void update_reconnect_parameters(grpc_subchannel *c) {
gpr_int32 backoff_delta_millis, jitter;
gpr_int32 max_backoff_millis =
GRPC_SUBCHANNEL_RECONNECT_MAX_BACKOFF_SECONDS * 1000;
double jitter_range;
backoff_delta_millis =
(gpr_int32)(gpr_time_to_millis(c->backoff_delta) *
GRPC_SUBCHANNEL_RECONNECT_BACKOFF_MULTIPLIER);
if (backoff_delta_millis > max_backoff_millis) {
backoff_delta_millis = max_backoff_millis;
}
c->backoff_delta = gpr_time_from_millis(backoff_delta_millis, GPR_TIMESPAN);
c->next_attempt = gpr_time_add(gpr_now(GPR_CLOCK_REALTIME), c->backoff_delta);
jitter_range = GRPC_SUBCHANNEL_RECONNECT_JITTER * backoff_delta_millis;
jitter =
(gpr_int32)((2 * generate_uniform_random_number(c) - 1) * jitter_range);
c->next_attempt =
gpr_time_add(c->next_attempt, gpr_time_from_millis(jitter, GPR_TIMESPAN));
}
static void on_alarm(void *arg, int iomgr_success) {
grpc_subchannel *c = arg;
gpr_mu_lock(&c->mu);
@ -586,6 +626,7 @@ static void on_alarm(void *arg, int iomgr_success) {
connectivity_state_changed_locked(c, "alarm");
gpr_mu_unlock(&c->mu);
if (iomgr_success) {
update_reconnect_parameters(c);
continue_connect(c);
} else {
GRPC_CHANNEL_INTERNAL_UNREF(c->master, "connecting");
@ -603,18 +644,20 @@ static void subchannel_connected(void *arg, int iomgr_success) {
GPR_ASSERT(!c->have_alarm);
c->have_alarm = 1;
connectivity_state_changed_locked(c, "connect_failed");
c->next_attempt = gpr_time_add(c->next_attempt, c->backoff_delta);
if (gpr_time_cmp(c->backoff_delta,
gpr_time_from_seconds(60, GPR_TIMESPAN)) < 0) {
c->backoff_delta = gpr_time_add(c->backoff_delta, c->backoff_delta);
}
grpc_alarm_init(&c->alarm, c->next_attempt, on_alarm, c, now);
gpr_mu_unlock(&c->mu);
}
}
static gpr_timespec compute_connect_deadline(grpc_subchannel *c) {
return gpr_time_add(c->next_attempt, c->backoff_delta);
gpr_timespec current_deadline =
gpr_time_add(c->next_attempt, c->backoff_delta);
gpr_timespec min_deadline = gpr_time_add(
gpr_now(GPR_CLOCK_REALTIME),
gpr_time_from_seconds(GRPC_SUBCHANNEL_MIN_CONNECT_TIMEOUT_SECONDS,
GPR_TIMESPAN));
return gpr_time_cmp(current_deadline, min_deadline) > 0 ? current_deadline
: min_deadline;
}
static grpc_connectivity_state compute_connectivity_locked(grpc_subchannel *c) {

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